Spruce is the most commonly used structural timber, sourced from the Norway spruce (Picea abies). It is light, affordable, easy to work with, and available everywhere. Virtually all joists, rafters, battens, and strips in a building structure are made of spruce.
Properties
Property
Spruce
Durability class
IV-V (not durable outdoors)
Colour
Light yellow to white
Density
±450 kg/m³
Workability
Very good
Price
Low (cheapest structural timber)
Strength
Sufficient for structural use
Where is spruce used?
Spruce is the workhorse of construction:
Application
Example
Roof structure
Rafters, purlins, trusses
Timber frame
Studs, rails, top plate, bottom plate
Battening
Behind plasterboard, for insulation
Formwork
Temporary timber for concrete pouring
Interior trim
Tongue-and-groove boards, skirting, mouldings
Furniture
Budget furniture (painted)
Spruce outdoors
Untreated spruce is not suitable for outdoor use. It rots within 2-5 years. Solutions:
Pressure-treated — Treated under pressure, lasts 15-20 years
Painted — Good covering exterior paint, repaint every 5-7 years
Structurally protected — If the wood stays dry (under a roof cover), it lasts lon Service life of spruce outdoors, untreated versus protected. ger
For unprotected outdoor applications, Douglas fir, larch, or hardwood are a better choice.
Spruce vs. pine
Spruce
Pine
Tree
Norway spruce
Scots pine
Colour
Lighter, whiter
More yellow, more grain
Knots
Smaller, lighter knots
Larger, darker knots
Resin content
Less
More
Price
Comparable
Comparable
Application
Structural timber
Furniture, floorboards, decorative work
In practice, spruce and pine are often used interchangeably. The difference is small.
